Re-tiling/waterproofing old plaster walls

[tilenoobie0]

Hey everyone,

I'm renovating a small 1960s condo bathroom. 2 of the walls in the bathroom are solid 2.5" cement based plaster with wire mesh lathe (no studs) and the other 2 I believe are drywall (theses are shared walls between units)

The 60 year old tiles are letting go from the thinset in spots. My plan is to remove the tile and thinset (the original mortar thinset looks to be in great condition) and patch and paint the areas where there will be no tile, and re-apply thinset and tile around the tub/shower area. Does this sound feasible? Should I apply red gard? I figure since thinset alone has stood the test of time I don't need to red gard?

I popped off a tile from the plaster wall and scraped away the thinset and it looks like it'll leave a paintable surface, but I haven't tested the drywall. Any tips? My plan is to use porcelain and I'm not sure what type of thinset I should use.

Thanks in advance

[Davy]

A picture or two would help us understand better. If you have sheetrock walls in the tub/shower area then you will want to screw cement board over it and apply Redgard (Home Depot) or Auqa Defense (Lowes) over the CBU. If the mud wall is in the shower area, I'd go ahead and cover the mud with waterproofing while you are at it. Be sure and get all the old thinset off first. The waterproofing will make it easier to tile.

[tilenoobie0]

Here are some pictures of the project. I began demo today and was very surprised. 3 (maybe all 4) walls are 100% plaster with metal lathe, very thick in spots.

I tested a spot with a grinder diamond cup/vacuum setup and the thinset is coming of nicely. The wall behind the toilet will be a bit tougher - the plaster is not finished and thinset was put directly onto the portland based plaster.

My plan is to remove all old tile (including floor), use a diamond cup grinder to level out and remove all the thinset. Then 12x24 porcelain tile, up to the ceiling around the tub/shower and on the floor. The plan for the areas walls where tile will not be replaced is to skim with plaster for a paintable finish.

There is no waterproofing currently. Would a red gard like product be a good idea in the tub area? Would I use a modified thinset for the new wall tile? The floor is concrete(tall building, the slab is immaculate), would I set the tile with modified thinset as well?

I'm a novice when it comes to this type of reno - so any and all advice is appreciated.

[Davy]

Sometimes water will penetrate thick mud walls, sometimes it won't. I use felt paper behind my mud and lath just in case but I doubt there is felt behind your mud. It's up to you about using Redgard or other waterproofing. Yes, I would use a modified thinset.